Development environment setup

AGENTS.md

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+## Cursor Cloud specific instructions
+
+This is a Rust + Node.js native addon library (`@bsdiff-rust/node`) using NAPI-RS. It implements bsdiff/bspatch binary diff/patch algorithms. There are no external services (no databases, no HTTP servers, no Docker required for local dev).
+
+### Key commands
+
+All standard dev commands are in `package.json` scripts — see README.md for details. Quick reference:
+
+| Task | Command |
+|------|---------|
+| Install deps | `pnpm install` |
+| Build native addon (release) | `pnpm build` |
+| Build native addon (debug) | `pnpm build:debug` |
+| Run tests | `pnpm test` |
+| Lint | `pnpm lint` |
+| Format | `pnpm format` |
+| Benchmark | `pnpm run bench` |
+
+### Non-obvious caveats
+
+- **Rust version**: The napi v3 dependencies require Rust >= 1.88. The pre-installed Rust toolchain may be too old. Run `rustup default stable` after `rustup update stable` if `pnpm build` fails with `edition2024` or version errors.
+- **Test resources**: Tests require two zip files that are NOT checked into git. They must be downloaded before running `pnpm test`:
+  ```
+  curl -L -o test/resources/react-18.1.0.zip "https://github.com/facebook/react/archive/refs/tags/v18.1.0.zip"
+  curl -L -o test/resources/react-19.1.0.zip "https://github.com/facebook/react/archive/refs/tags/v19.1.0.zip"
+  ```
+- **`cargo fmt --check`** will report diffs because the Rust source uses 4-space indentation while `rustfmt.toml` specifies `tab_spaces = 2`. This is a pre-existing inconsistency in the repo.
+- The native `.node` binary is generated in the workspace root (e.g., `node.linux-x64-gnu.node`) and is loaded by `index.js`. You must run `pnpm build` before tests or any usage.
+- `lint-staged` + `husky` are configured in `package.json` but the `.husky/` directory is absent, so git hooks are not active.